Radio valves employing gallium



Filed May 27, 1950 l vvvvvv I molten; Moreover, it is known that it is possible to Patented July 5, 1932 UNITED sT rEs PIERRE onEUzE; E PARIS, FRANCE, ASSIGNO 'ro ,so IErE, nmunnssoinnrrr reuns ET INDUSTRIELLES, or RABS,; FRANGE RADIO vALvEs m mas earma- I i Application filed May 2?, i930. Serial mi; 456,255yand in France Jur st-1925;:

Gallium is a white, hard, slightly malleabl'e' It oxidizes but little and does notvolatilize' at all, even at a red heat. It unites all the conditions for obtaining an abundant emission of electrons with the aid of very low temperatures. Finally it possesses the prop erty of adhering strongly to glass when it is cover a metallic filament with a very light layer of a glass having a high fusing point,

such as boro-silicate glass.

The object of the present invention is to employ gallium or its salts forconstructing a valve which can be heated at extremely low temperatures either directly with continuous or alternating current from the mains (with a transformer and resistance) or with bat-f.

tery or accumulator elements of very low power or by any external source of heat.

Nothing has to be modified in the existing form and arrangements of radio valves excepting in the filament. The latter, which is of a suitable metal of suitable diameter, is covered with a layer of boro-silicate glass.

The filament covered with glass then receives a more or less thick coating of gallium either by dipping in the liquid state and slow- 1y cooling, or by pulverizing under a low pressure, or by a galvanoplastic or electrolytic process or by casting it, etc;

The invention will now be described with reference to the accompanying drawing in which:

Figure 1 is a sectional view'ofa filament.

according to the. invention.

Figure 2 is a dlagrammatlc. view of'a radio valve embodying afilament according to the The arrangement shownin Figural of the drawing comprises a filament 1' made of suit 1 any other way.

able metal, a layer 'of' glassfi on thisvfilament and a coating of gallium 3 covering the glass.

- =.The filament thus prepared is then arranged in the claws of thefilament supporting wires of avalve, and the subsequent operations for completing the'valve aresimilar to those usually carried out (positioning the grid and the plate, creating the vacuum, etc.)

Figure 2 shows adiagrammaticsectional view of a valve comprisinga filament such. as that shown in Figure 1. In this figure, 4.

and 5 are the leadsto the filament 6, 9,is the" grid and the plate. Provision may be made. of a transformer 7 and a resistanceS contained in the base of the: valve.

Instead of forming the 'filamentfas. de-

scribed ab ove, the gallium may be arranged in the form ofa solid or hollow disc in the in teriorof which the heating element is ar- In the case shown in this figure, the metal heating filament covered with .glass is ar- 7 V ranged across a diameter of the gallium disc; but it may also be arranged in the form of a spiral, as shownat 13 in the plan ;view in L 80 7 i In the example shown in Figure 5, the metal Figure 4.

heating filament 14 is arranged inside a glass 7 support 15 receivingthe gallium disc 16.

In the case when it is desired-to obtain the heating by other means than electricity, the source of'heat may continue to be external, 7

andbe composed of vapoursor hot air with a generator which may be a simple alcohol lamp or a petrol lamp with a temperature regu-l lator.

This regulator may beformed by a simple strip of zinc or iron, closing the source of heat when the temperature reaches31?,1

this regulation being similar to that employed in heating stoves using petrol or operated in As will be seen, this valve permits with very different and numerous accessory heating;

means',jver.y varied types of lamps to be obtained. These lamps are capable of permit-:

j T: f 3 p 1,866,195

ting numerous mountings which avoid the greater part of the dangers which are encountered in practice. They also permit the weight of apparatus and the overall dimensions to be reduced and to obtain detection and amplification :under .themo st favorable ternating currents.

conditions and also the rectification .of al- I What I claim is:

' -1.-A filament for radiova'lves composed T of a metal coated with a layer of glass, the

. Vglass being in turn coated with a layer of,

gallium. I

2. 'A filament for radio valves composedof. v

a metal, coated with a layer of fire resisting glass, the glass being in turn coated with a i 7 layer of gallium. 7 .In'testimony whereof I have-signed my name to this specification.

PIERRE CRE ZE." 

